Apparatus and Method of Moving Fluid in a Rotating Cylinder

ABSTRACT

The invention may utilize shaft horsepower for rotating cylinders to move a fluid in an axial direction within the cylinder. The cylinder may comprise a spiral blade on or in its inner surface with a pitch relative to a central axis of the cylinder. The blade&#39;s pitch may be variable or uniform with respect to the central axis. In some applications, plural blades may be positioned within the cylinder. The invention is particularly suitable for imparting kinetic energy sufficient to assist with the evacuation of condensate from a paper dryer cylinder with reduced or no blow through steam. The invention also has applications for spinner wheels.

RELATED APPLICATION

This application claims the benefit of U.S. provisional application No.62/331,246, filed May 3, 2016, which is incorporated by reference.

TECHNICAL FIELD

This disclosure relates to apparatuses and methods of moving fluid in anaxial direction in rotating cylinders, particularly (but withoutlimitation) cylinders used in continuous manufacturing processes inwhich the cylinders have a heat transfer function. Examples of suitablecylinders are heated dryer drums used in paper manufacturing and coolingcylinders used in spinning metal and/or mineral wool.

BACKGROUND

Paper products may be made using rotating dryer drums, and metal woolmay be made using rotating spinner wheels. While both use rotatinghollow cylinders—a dryer drum or the shell of a spinner wheel—their sizeand function are different. Many conventional dryer drums have a largediameter (usually about 1-3 meters), a length that is multiple timesgreater than the diameter (usually between about 5-11 meters), operateat rotational speeds of about 300 meters per minute or more, and areused to heat paper web to evaporate water therein. By contrast, manyconventional spinner wheels have much smaller diameters (usually betweenabout 50-60 cm), a length that is usually less than the diameter(usually between about 25-35 cm), operate at relatively higherrotational speeds of about 5,000 rotations per minute or more, and maybe fully filled with coolant to absorb heat from a shell used to spinthreads of molten material. Because of their differences in size andoperational conditions, art relating to dryer drums may not be analogousto spinner wheels and art relating to spinner wheels may not beanalogous to dryer drums. However, in conventional configurations forboth applications, shaft horsepower is generally used to rotate a hollowcylinder, not to move fluid within the cylinder in an axial direction,i.e., from one end or location within the cylinder to another.

Paper Manufacturing.

Despite increasing energy costs, and efforts to reduce environmentallyharmful emissions therefrom, energy intensive methods of making paperproducts have remained largely unchanged for more than a century. Dryingcellulosic pulp to form paper consumes most of the energy—up to 80% ofthe total—used by conventional methods of making paper. For example,conventional methods may use more than 1 million joules per pound ofwater to be evaporated from a paper web. Any improvement that wouldincrease efficiency, even slightly, would result in substantial savingsto the industry.

The resistance to heat flow from the steam inside the dryer drum to thepaper web consists of a complex conduction system with several layers ofthermal resistance. Condensate must be removed from the drum becauseexcess liquid in the drum inhibits heat transfer from the steam insidethe drum to the paper web outside. Condensate also requires additionaldrive power for drum rotation.

For the steam inside a dryer drum, the internal condensate layer is thefirst major resistance to heat transfer. The level of resistance issubject to multiple factors such as condensate thickness and behavior.During normal steady state operation of the system, condensate iscontinuously removed, but some condensate is always present inside thedrum. As rotational velocities increase to operational levels,centrifugal forces progressively increase on the condensate within thedrum until it forms a substantially uniform, annular layer on the innersurface of the drum, a phenomenon called “rimming” See FIG. 5C. Forexample, rimming behavior may occur in a typical dryer drum with adiameter of 2 meters at rotational velocities of approximately 300meters/minute or greater. Condensate that is rimming has generallylaminar flow.

To remove condensate from a rotating dryer drum, a siphon may be used.(However, siphons are not generally used in spinner wheels.) In thepaper making context, condensate must be moved up through a siphon tube(i.e., away from the inner surface of the cylinder and generally towarda central axis of the cylinder) to the outlet. Rotary siphons, whichrotate with the dryer drum, and stationary siphons, which do not, aredescribed in U.S. Pat. No. 5,335,427, issued Aug. 9, 1994, which ishereby incorporated by reference in its entirety.

In conventional configurations, the difference in pressure between ahigher-pressure “supply” steam header and lower-pressure “return”condensate header is used to remove the condensate from the cylinder. Tofurther ease its removal, some “supply” steam may be evacuated with thecondensate, breaking it up into an aspirated vapor and therebydecreasing its density. The vapor is then carried out as a two-phaseflow. (The vapor arises from two sources: (i) supply steam and (ii)condensate flashing into a vapor state due to the pressure drop as ittravels through the siphon tube.) The “supply” steam that blows throughthe cylinder without condensing and giving up its latent heat to thedrum system is known as “blow through” steam.

For a conventional dryer drum configuration, significant amounts of“blow through” steam, representing up to 35% or more of total steam, maybe required to evacuate the condensate from the rotating dryer drum. Forexample, rotary siphons, which rotate with the dryer drum and requirecondensate to overcome centrifugal forces in the siphon shaft, mayrequire up to 35% or more blow through steam. By contrast, becausestationary siphons may utilize the relative velocity and momentum of thecondensate to help move it up a stationary siphon shaft, they mayrequire less blow through steam than rotary siphon configurations.

Although conventional means exist to promote heat transfer through arimming condensate later, they principally act by creating turbulence.See, for example, U.S. Pat. No. 4,195,417, issued Apr. 1, 1980, and U.S.Pat. No. 7,673,395, issued Mar. 9, 2010, both of which are herebyincorporated by reference in their entirety, showing plural turbulencebars positioned parallel to the drum's central axis. While suchturbulence bars may disrupt a rimming condensate layer as it overtopsthe bars, they are not pitched at an angle that would tend to move thecondensate in an axial direction (e.g., toward the mouth of a siphon forevacuation).

Metal Wool Manufacturing.

Spinner wheels may be used to manufacture metal wool and/or mineralwool. Molten material is dripped or applied onto the shell of a fastrotating spinner wheel, creating strands of the “wool” that coolmid-air. The molten material's high temperatures damage the shell of thespinner wheel, which must be regularly replaced at significant expense.Although conventional systems circulate water within a filled cylinderin an attempt to cool them, the cylinder's extremely high rates ofrotation (e.g., typically between 5,000 and 6,500 rpm), inhibitcirculation near the inner surface of the cylinder and prevent effectiveconvective cooling within the cylinder. Without effective cooling, thecylinders become damaged and must be replaced.

SUMMARY

There is a need to utilize shaft horsepower for rotating cylinders tomove a fluid in an axial direction within the rotating cylinder.Nonlimiting examples of a suitable cylinder include a dryer drum and aspinner wheel shell. In the paper manufacturing context, a significantamount of energy is lost because of blow through steam requirementsranging from 10-35% of the total steam delivered to the system.Accordingly, if steam could be used almost exclusively for drying paperpulp, instead of moving and removing condensate, up to 35% of energysavings could be realized. Likewise, for wool spinning applications, ifwater could be moved and circulated more efficiently within a coolingcylinder, greater convection could prevent damage from molten metals,significantly reducing shell replacement costs.

In one embodiment of the invention, a helical blade may be positioned onthe inner surface of a cylinder such that the blade rotates with thecylinder. The blade may follow a spiral path having a central axis andone or more loops. The central axis of the spiral path may be collinearwith a central axis of the cylinder. In some forms of the invention, theblade may be formed as one or more grooves in the inner surface of thecylinder wall itself or be comprised of plural, non-unitary structuresthat effectively act as a blade for moving fluid in an axial directionwithin the cylinder. Some embodiments may comprise plural blades, eitherat least in parallel or end-to-end.

A helical blade preferably has at least a portion of the blade with apitch with respect to its central axis greater than 0 degrees and morepreferably greater than 3 degrees and even more preferably greater than5 degrees. To maximize axial movement of the fluid within a rotatingcylinder, optimizing the blade pitch and position in the cylinderdepends on several factors that depend on the implementation. Somefactors include: the size and shape of the cylinder, the fluid'scentripetal acceleration, viscosity, and specific gravity, and netpressure differential between the fluid inlet and outlet of thecylinder.

In some embodiments, the pitch may vary, i.e., may be different atdifferent points, along the length of the blade. For example, a firstportion of the blade (e.g., proximate to a first end of the cylinder)may have a first pitch with respect to the central axis (e.g., about 70degrees, 80 degrees or substantially perpendicular to the central axis,i.e., about 90 degrees, or any subrange). A second portion of the blade(e.g., proximate to a second end of the cylinder) may have a secondpitch that may be different than the first pitch (e.g., about 60degrees, about 45 degrees, or substantially parallel, i.e., about 0degrees, or any subrange).

In some embodiments, a portion of the blade between first and secondpoints may have a pitch that varies along the length of the blade. Forexample, in one embodiment comprising a blade with a varying pitch, theblade's pitch at a third point between the first and second points maybe different than the pitches at the first and second points. In anotherexample, a portion of the blade at one end may have a first pitch ofabout 90 degrees, a second pitch at the other end of about 0 degrees,and a pitch of about 45 degrees midway between the two ends. In otherwords, if the interior of a hollow cylinder was hypothetically separatedinto six zones having an equal axial length, a blade positioned on theinner surface of the cylinder may have at least a portion of the bladein each zone with the following linearly varying pitches: 90 degrees, 72degrees, 54 degrees, 36 degrees, 18 degrees, and 0 degrees. Pitches mayvary linearly, as in the foregoing example, or non-linearly. Numerousalternative varying pitch configurations are possible, however, rangingfrom 90 to 0 degrees and all subranges between them.

In addition or alternatively, at least a portion of the blade may have auniform pitch that does not vary in the axial direction. (See, e.g.,FIGS. 3A and 3B.)

As the cylinder and blade rotate together, fluid on the inner surface ofthe cylinder may be channeled along the helical blade in at least apartially axial direction. Generally, the velocity of such fluid may beinversely proportional to the blade's pitch (relative to the centralaxis). For example, fluid channeled along a portion of a blade with arelatively higher pitch (e.g., 70-90 degrees) may have a lower velocitythan fluid channeled along a portion of the blade with a relativelylower pitch (e.g., 70-45 degrees or less). In this example, as fluid ischanneled along the blade in the cylinder, the fluid velocity in anaxial direction increases, i.e., accelerates, as the pitch of the bladedecreases in an axial direction. In some embodiments, the pitch maydecrease to zero, becoming substantially parallel with a central axis ofthe cylinder.

Liquid fluid rimming on the inner surface of a cylinder forms asubstantially annular shape. If the fluid is incompressible (e.g.,liquid water), the fluid that is incident to, and channeled along, ablade may move at least some of the remaining fluid body in the sameaxial direction of its flow. In this manner, at least one helical blademay move an entire fluid body in an axial direction, even though theblade may be in contact with only a portion of such fluid body.

An inlet of a siphon may be positioned to maximize the momentum of thefluid to assist with its removal from the cylinder. At sufficientrotational speeds, the kinetic energy of the fluid may assist withovercoming the centrifugal forces within the siphon. In someembodiments, a mouth of a siphon may be positioned proximate to a bladewithin the cylinder.

Paper Manufacturing.

In one embodiment, a helical blade may be positioned on the innersurface of a dryer drum. As the dryer drum and blade rotate, supplysteam may condense on the inner surface of the cylinder. Such condensatemay be channeled along the helical blade in an at least partially axialdirection along the length of the dryer drum. In some embodiments, aninlet of a siphon may be positioned at one end of the blade, and, atsufficient rotational speeds, the total kinetic energy the condensatemay assist with overcoming the centrifugal forces within the siphon.This may allow the drive motor rotating the dryer drum to act as aprincipal means of evacuating condensate, significantly reducing oreliminating the need for blow through steam.

The blade may be sized and shaped to act as a barrier such that thecondensate cannot overtop the blade at rimming speeds. In addition oralternatively, at least a portion of the blade may be designed so thatcondensate overtops the blade. The exact shape of the blade may dependon the system's optimal operating conditions and condensate thickness,but one preferred form is an r-shape.

In one embodiment, one or more variable pitch blades may promote asubstantially uniform depth of the condensate layer across the axiallength of the cylinder. In the papermaking context, this may enableuniform resistance to heat transfer from supply steam, through thecondensate layer and dryer drum itself, and across the width of theexternal paper web.

In an alternative embodiment, a constant pitch blade (i.e., a blade thatis uniform and does not vary in the axial direction) may be used forsystems that do not require highly uniform heat transfer or where thesystem includes other means to handle accumulation of fluid at one endof the cylinder. This is in part because a constant pitch spiral blademay tend to have a non-uniform condensate thickness across the axiallength of the cylinder, with a smaller condensate layer thickness at oneend of the cylinder (e.g., from which condensate may be drawn) and agreater condensate layer thickness at the other end (e.g., wherecondensate may be directed, near a siphon outlet), which may lead to anon-uniform heat profile across the external paper web.

Metal Wool Manufacturing.

In one embodiment, a helical groove may be formed in the inner surfaceof a shell of a spinner wheel. The helical groove may follow a spiralpath having a central axis and one or more loops. In some embodiments,the shell may be partially filled with any suitable coolant, such aswater or ethylene glycol. In other embodiments, the shell may besubstantially fully filled. As the shell rotates, fluid may be channeledalong the helical groove in an axial direction. In some embodiments, thegroove may have a variable pitch. In other embodiments, the groove mayhave a uniform pitch.

In addition or alternatively, a siphon may be positioned within aspinner wheel. In some embodiments, a stationary siphon may bepositioned within a partially filled spinner wheel.

In addition or alternatively, a helical blade may be positioned within aspinner wheel. The helical blade may rotate with the spinner wheel,which may be substantially filled. The helical blade preferably has anouter diameter that may be less than the inner diameter of the shell orcage, if any, whichever is smaller. In some embodiments, the blade mayhave a variable pitch. In other embodiments, the blade may have auniform pitch.

In some embodiments, a spinner wheel comprising blades and/or groovesmay facilitate heat transfer from the outside of the shell to thecoolant. Grooves on the inner surface of the shell increase the surfacearea exposed to the coolant. In addition or alternatively, a blade maybe positioned to contact the inner surface of the shell such that itacts as a conductive heat sink.

The above summary is not intended to describe each illustratedembodiment or every possible implementation. These and other features,aspects, and advantages of the invention that will become betterunderstood with regard to the accompanying drawings, description, andclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, serve to illustrate exemplary embodiments, forms, and aspects ofthe invention and to explain principles and advantages thereof:

FIG. 1A is a perspective view of a first embodiment of the invention fora dryer drum.

FIG. 1B is a side elevation view of the embodiment shown in FIG. 1A.

FIG. 1C is a detail of FIG. 1A.

FIG. 1D is a cross-sectional view of the embodiment shown in FIG. 1C.

FIG. 2A is a perspective view of a second embodiment for a dryer drum.

FIG. 2B is a side elevation view of the embodiment shown in FIG. 2A.

FIG. 3A is a perspective view of a third embodiment for a dryer drum.

FIG. 3B is a side elevation view of the embodiment shown in FIG. 3A.

FIG. 4A is a perspective view of a fourth embodiment for a dryer drum.

FIG. 4B is a side elevation view of the embodiment shown in FIG. 4A.

FIGS. 5A-C show three stages of condensate behavior in a rotating dryerdrum.

FIG. 6 is a schematic view of a one embodiment for a spinner wheel.

FIG. 7A is an exploded perspective view of a fifth embodiment for aspinner wheel.

FIG. 7B is a cross-sectional view of FIG. 7A.

FIG. 7C is a partially exploded perspective view of the embodiment shownin FIG. 7A.

FIG. 7D is a side elevation view of the embodiment shown in FIG. 9A.

FIG. 7E is a cross-sectional view of FIG. 7D.

FIG. 7F is a detail view of FIG. 7C.

FIG. 7G is a detail side elevation view of a siphon 180 with a shoe 184.

FIG. 8A is a partially exploded perspective view of a sixth embodimentfor a spinner wheel.

FIG. 8B is a detail view of FIG. 8A.

FIG. 8C is a detail side elevation view of a siphon 180 with a scoop186.

FIG. 9A is a partially exploded perspective view of a seventh embodimentfor a spinner wheel.

FIG. 9B is a side elevation view of the embodiment shown in FIG. 9A.

FIG. 9C is a cross-sectional view of FIG. 9B.

FIG. 10A is a partially exploded view of an eighth embodiment for aspinner wheel.

FIG. 10B is a side elevation view of the embodiment shown in FIG. 10A.

FIG. 10C is a cross-sectional view of FIG. 10B.

FIG. 11A is a partially exploded perspective view of a ninth embodimentfor a spinner wheel.

FIG. 11B is a side elevation view of the embodiment shown in FIG. 11A.

FIG. 11C is a cross-sectional view of FIG. 11B.

FIG. 12 is an exploded view of a tenth embodiment for a spinner wheel.

DESCRIPTION

Apparatus and methods of moving fluid in a rotating cylinder aredescribed. An apparatus embodying features of the present invention isshown in FIGS. 1A-D. FIG. 1A shows a cylinder 100, such as a sealeddryer drum for making paper products. The cylinder 100 has a first end102 and a second end 104. The cylinder 100 may be supported by supportmembers 110 attached to shaft 120. A motor (not shown) drives the shaft120 to rotate the cylinder 100. The interior of cylinder 100 may be influid communication with an inlet (i.e., the annulus between the shaft120 and condensate outlet 124) through which a heating fluid, such assteam, may be pumped into the cylinder via shaft 120. As explained inmore detail below, condensate may be removed from the cylinder 100 viarotary siphon 200 through outlet 124. Alternative embodiments mayutilize a stationary siphon.

As shown in FIG. 1A, a spiral blade 300 may be positioned on innersurface 101 of cylinder 100 such that the blade 300 rotates with thecylinder 100. The blade 300 may be fixedly or removably attached to thecylinder 100, including by friction, magnets, welding, crossbeamsextending across the interior of the dryer drum, or hoop segments (notshown). If scale is present on the inner surface 101, it is preferablyreduced or removed before the blade 300 may be installed and/orpositioned thereon.

The blade 300 may be formed from any suitable material that canwithstand the operating environment within the cylinder 100, such asstainless steel, carbon steel, aluminum, and other corrosion-resistantalloys and polymers. In addition or alternatively, the blade 300 may beformed as a groove 370 in the inner surface of the cylinder 100 itself(see e.g., FIG. 12). The blade 300 may be coated with a material thatprevents scale build up, such as a quench-polish-quench (or “QPQ”)process.

As shown in FIG. 1B, one embodiment of the blade 300 comprises six loopsaround a central axis 190, wherein the blade 300 has a pitch withrespect to the central axis 190 that varies in the axial direction. Thefirst loop proximate to first end 102 forms a pitch with the centralaxis 190 that may be substantially perpendicular to the central axis190. The second pitch 1310 and successive pitches 1312, 1314, 1316, and1318 have gradually lesser slopes until the end of the blade 300approaching second end 104 may be substantially parallel with centralaxis 190. Accordingly, the distance 1320 between the first loop and thesecond loop may be less than the distance 1322 between the second andthird loop, which may be less than the distance 1324 between the thirdand fourth loop, and so on.

By adjusting the pitch of the blade 300, the velocity of the fluid at agiven point in the drum may be increased or decreased. Accordingly,alternative embodiments may have more or fewer loops with varying and/oruniform pitches, depending on the length of the cylinder, its diameter,steady-state rotational velocity and centripetal force, viscosity of thefluid, pressure differential between inlet and outlet, and desired axialvelocity of condensate at a given point, e.g., proximate to the mouth ofa siphon.

Viewing FIG. 1A, as the pitch of the blade 300 decreases along the axiallength of the dryer drum 100 from the first end 102 to the second end104, the velocity of the condensate increases in the axial directiontoward siphon 200. In this manner, a blade 300 with a variable pitchprevents condensate from collecting at the second end 104 of cylinder100, thereby promoting more uniform heat transfer from steam to thedryer drum 100.

By contrast, FIG. 3B shows an alternative embodiment of the blade 305with four loops and a uniform pitch respect to the central axis 190,which remains constant in the axial direction. The first loop proximateto the first end 102 forms a pitch 3310 with the central axis 190. Thepitches 3312, 3314, 3316 for the second, third, and fourth loops may beapproximately the same as the first pitch 3310. Likewise, each distancebetween loops, 3320, 3322, 3324, 3326 may be approximately the same.Because of the uniform pitch, in this configuration the condensate maytend to have a smaller depth on first end 102 and a somewhat greaterdepth toward the second end 104, which (as explained above) can lead toa non-uniform heat profile on the outer surface of the dryer drum 100.

Returning to FIG. 1A, in operation steam may be pumped into the cylinder100 via shaft 120. As the steam gives up its latent heat, condensateforms (not shown) on the inner surface 101. Viewing FIGS. 5A-C, as therotational velocity of the cylinder 100 increases from nil to steadystate operating speeds, centrifugal forces acting on condensate 500gradually overcome the force of gravity in three successive stages:puddling (FIG. 5A), cascading (FIG. 5B), and rimming (FIG. 5C). In thepuddling stage shown in FIG. 5A, the force of gravity predominates andfluid 500 tends to puddle near the bottom of the cylinder. Next, in thecascading stage shown in FIG. 5B, friction causes the fluid 500 totravel up the inner surface of the cylinder 100 and cascades back to thebottom. Cascading action consumes significant power from the drivemotor. Finally, as shown in FIG. 5C, the cylinder's 100 centrifugalforces overtake the force of gravity and the fluid 500 starts rimming toform a substantially uniform, annular layer. In general, a cylindersystem comprising one or more blades 300 within a rotating cylinder 100may tend to reach a rimming state at lower rotational velocities than ifthe blade 300 was absent.

Viewing FIG. 1A, as the cylinder 100 rotates at steady-state rimmingspeeds, the blade 300, which rotates with cylinder 100, moves condensatefrom the first end 102 of cylinder 100 to the second end 104 of cylinder100. A siphon 200 may be positioned proximate to the second end 104 tofacilitate evacuation of condensate from the cylinder 100 through outlet124. In other words, the blade 300 may be shaped and positioned on theinner surface 101 of the cylinder 100 such that the condensate may bechanneled along the blade toward the second end 104 of the cylinder 100(and ultimately to the outlet 124). Condensate may tend to accelerate asit travels along the variable pitch blade 300, i.e., as the pitch of theblade 300 decreases and becomes aligned with central axis 190 (see alsoFIG. 1B). A siphon 200 may be positioned proximate to the second end 104to facilitate evacuation of condensate from the cylinder 100 throughoutlet 124.

At steady-state rimming speeds, the force applied by the blade 300 onthe condensate may be transmitted throughout the incompressiblecondensate medium (not shown). In other words, the force of the blade300 on condensate incident to blade 300 may be transmitted through therimming condensate medium, causing the entire body of fluid to flowtoward the second end 104. Condensate is preferably accelerated in anaxial direction by the blade 300 to speeds that may be sufficient to atleast enter a rotary siphon 200. In more preferably embodiments, thefluid may have sufficient moment to also overcome centrifugal forceswithin the siphon 200 using little to no blow through steam, and exitthe cylinder 100 through outlet 124.

In some embodiments, a rotary siphon 200 may be preferred because it canbe fixedly positioned on or near a terminal end of the blade 300proximate to the outlet 124. The rotary siphon 200 also allows for avery small gap (less than 8 mm) between the siphon inlet and the innersurface 101 of cylinder 100. This gap may define the thickness of thecondensate layer, thereby reducing resistance to heat transfer from thesteam to the dryer drum 100.

Turning to FIG. 1D, the blade 300 may be r-shaped with a height 322 andwidth 320. The base of blade 300 may form an angle 324 with a tangentialplane of the inner surface 101. In one preferred embodiment, the blade300 has a height 322 of less than about 10 cm and angle 324(approximately 80 degrees) to prevent condensate from over-topping theblade 300 under rimming conditions. Alternative embodiments of blade 300may utilize a vertical cross-section, an L-shape, or other cross-sectionshapes. The base of blade 300 may form an angle 324 that is preferably90 degrees or less. Other embodiments may have a blade 300 that forms anobtuse angle 324. Other embodiments may have a height 322 of between 5cm to 20 cm or more or any subrange therein.

Certain configurations may require blow through steam, but such blowthrough steam is preferably less than 15% of the supply steam, and morepreferably less than 1-10% of the supply steam, and even more preferablyless than 0.5-5% of supply steam, introduced into the dryer cylinder.

In other configurations without blow through steam, an end of the blade300 may form a liquid seal with a siphon 200, i.e., the mouth of thesiphon 200 may be substantially submerged in the condensate, enhancingevacuation efficiency and flow monitoring. Because the liquid sealprevents steam from exiting the cylinder through the siphon 200, thesteam may be forced to impart substantially all its latent heat ofvaporization to the system before condensation and evacuation, allowingfurther process heating optimization of the steam heating medium.

In the context of manufacturing paper products, the apparatus andmethods described herein provide three significant advantages over anunmodified dryer drum or a drum with mere turbulence bars.

First, the need to use blow through steam to remove condensate from thecylinder 100 may be significantly reduced or eliminated. The spiralshape of the blade 300 imparts a force to the condensate in an axialdirection and provides the means for moving condensate within thecylinder 100 toward the outlet 124. Thereby the rotation of the cylinder100 itself may be a principal source of the kinetic energy used forevacuating the condensate.

Second, unlike drums with turbulence bars, pitched blades 300 mayaccelerate condensate medium to turbulent flow velocities withoutinterrupting its path toward evacuation near the second end 104. Thisreduces the amount of time condensate resides within the cylinder aswell as reduces the heat resistance across the condensate layer.

Third, evacuating a single phase liquid eliminates the need for complexcontrol systems and allows for significantly improved flow measurements.In particular, vapor recompression devices and other components requiredfor recapturing two-phase flows with high levels of blow through steamare highly inefficient. Moreover, most conventional flow measurementtechnology cannot accurately measure two-phase flow comprisingcondensate aspirated at a siphon inlet because of widely divergent massdensity, specific gravity, and velocity profiles associated with suchmedia. A single phase liquid, by contrast, allows for highly accurateflow control, differential pressure control, and quantitativemeasurements using relatively inexpensive, conventional devices.

However, not all embodiments are required to have any or all theforegoing advantages.

Turning to FIGS. 2A-B and 4A-B, embodiments comprising plural variablepitch blades or blade segments are shown. FIG. 2A shows two variablepitch blades 300, 301 positioned in parallel, one rotated 180 degreesfrom the other. FIG. 4A shows three variable pitch blade segments 310,311, 312 connected to one another in series.

Viewing FIG. 2A, two blades 300, 301 may facilitate rimming ofcondensate within the rotating cylinder 100 at lower rotationalvelocities than configurations with a single blade 300 or no blade.Further, comparing FIG. 1B (showing one blade 300) and FIG. 2B (showingtwo blades 300, 301), at rimming speeds, the average distance betweenthe nearest blade and condensate at any given point on the inner surface101 of the cylinder 100 may tend to be less with two blades 300, 301than one blade 300.

In addition or alternatively, embodiments with two or more blades 300,301 may have one blade with more or fewer loops than the other blade orthe same or different pitch profile.

FIG. 3B shows a blade 305 having a uniform pitch relative to the centralaxis 190, wherein pitches 3310, 3312, 3314, and 3316 may beapproximately 45 degrees with respect to longitudinal axis 190. Theblade 305 may facilitate the movement of fluid from a first end 102 ofthe cylinder 100 to a second end 104. But, as explained above, in anembodiment with a uniform pitch blade 305 as shown in FIG. 3B, thecondensate layer may have a smaller thickness proximate to first end 102and tend to have a gradually greater thickness toward the second end104. In the context of a paper machine, a non-uniform condensate layermay lead to a non-uniform temperature profile for the paper web, becausea greater condensate thickness creates a greater resistance toconductive heat transfer from internal steam to the inner surface 101 ofthe cylinder 100. Accordingly, if a uniform pitch blade 305 is employed,it may be preferably in medium or low grade paper applications or otherapplications where non-uniform heat profiles may be acceptable.

FIG. 4B shows several variable pitch segments 310, 311, 312 arranged inseries along the longitudinal axis of the cylinder. Two continuoustransitions separate segments 310, 311 and segments 311, 312 of theblade 300. In this embodiment, both transitions may be located between asubstantially zero final pitch angle with respect to central axis 190,where one segment ends, and a pitch angle which is almost 90° at thebeginning of the next segment. In addition or alternatively, othertransitions and pitch angles could be used and optimized depending onthe size and rotational speed of the rotating cylinder and the number ofsegments and other optimization factors discussed in this disclosure.

At each successive segment, the velocity of condensate entering thesegment may be progressively greater than the previous segment and,therefore, the velocity of condensate exiting each segment may beprogressively greater. For example, the axial velocity of condensate maybe approximately nil at the first loop of segment 310 proximate to firstend 102. Condensate may then accelerate across the first segment 310before entering the second segment 311 and then further acceleratedbefore entering the third segment 312. Accordingly, use of pluralsegments may allow progressively higher condensate flow velocities alongthe longitudinal axis of the cylinder toward the end 104 of thecylinder. In some embodiments, a blade 300 comprising plural segments(e.g., as shown in FIG. 4B) may be configured to achieve greater axialfluid velocities than a single continuous segment (e.g., as shown inFIG. 1B).

Apparatuses embodying features of the present invention suitable forspinner wheels are shown in FIGS. 6-12. FIG. 6 shows a spinner wheeldrive system comprising a motor 151 powering a shaft 153 by a belt 152.A wheel 150 may be operably attached to the shaft 153 through a journal154 and rotate about a central axis 190. The system may further comprisea coolant exchanger 158. FIG. 6 further shows one wheel 150 formed inpart by a shell 170 with an outer surface 1705.

In operation, the wheel 150 may be at least partially filled with acoolant (not shown) and spun by a motor shaft 153 at high rotationalspeeds (e.g., 4,000 to 7,000 rotations per minute and any subrangebetween). In one application, molten metal may be dripped or poured ontothe outer surface 1705 of the shell 170, and, on impact with the outersurface 1705, the metal elongates to become thin strands of metal, alsoknown as “mineral wool” or “metal wool.” Without adequate cooling, theshell 170 may become damaged and must be replaced.

Turing to FIG. 7B, one embodiment of a spinner wheel 150 may comprise anouter endcap 175, a shell 170, and inner endcap 1751. A support cage 160may be positioned within the shell 170 and be coupled to the outer andinner endcaps 175, 1751. The inner endcap 1751 may be coupled to ajournal 154, which may translate shaft drive power to rotate the wheel150. Hub 161 may be coupled to journal 154. As shown in FIG. 7A, theforgoing elements are coupled to one another, respectively, by fasteners169. For example, the outer endcap 175 and inner endcap 1751 maycomprise a plurality of bores 1757 that align with bores 1608 in cage160. The cage 160 may be coupled to the outer and inner endcaps 175,1751 by fasteners 169 (see also FIGS. 7C, 8A and 9A). The inner endcap1751, in turn, comprises a plurality of bores 1756 that align with bores1545 in journal 154, and they are coupled together by fasteners 169.Viewing FIG. 7A, the outer and inner endcaps 175, 1751 may compriseflanges 1752. The shell 170 may comprise a plurality of notches 1753sized to operably couple with said flanges 1752 (see also FIGS. 7D, 8A,9A and 9B). Alternative embodiments may employ different or additionalcoupling means, such as welds, fasteners, and other coupling means.Alternative embodiments of a spinner wheel 150 may not comprise a cage160 (see, e.g., FIGS. 10-12) or a shell 170 without grooves 370 (see,e.g., FIGS. 10-11).

Turning to FIG. 7C, a shell 170 may be a hollow cylinder with a helicalgroove 370 in its inner surface 171. In one embodiment, the groove 370has a uniform pitch. Alternative embodiments of shell 170 may have agroove 370 with a varying pitch (see, e.g., FIG. 12) and/or pluralgrooves 370. The shell 170 may be coupled to an endcap 175. The endcap175 may have a flange 1752, and the shell 170 may have a notch 1753sized to operably couple with the flange 1752.

A cavity 165 may be defined by the shell 170 and inner and outer endcaps175, 1751. Cage 160 is positioned within the cavity 165, forming a gap1655 between the outer diameter of the cage 160 and the inner surface171 of the shell 170.

Viewing FIG. 7C, a spinner wheel 150 may comprise a hub 161 and a siphon180. At least a portion of the siphon 180 may be positioned within thehub 161 and may be supported by a bushing 181 (see FIG. 7B). The hub 161may have a plurality of apertures 1615 in fluid communication with inlet162 (see FIG. 7E), and the siphon 180 may be in fluid communication withthe outlet 167 (see FIG. 7E). Except for the siphon 180, which isstationary in the embodiment shown, the other components of the wheel150 rotate in direction 155 about central axis 190 (see FIG. 7E).Alternative embodiments may comprises a rotary siphon.

Turning to FIG. 7E, fluid (not shown), such as coolant, may becirculated within gap 1655 to cool the shell 170. Fluid may enter thewheel 150 under pressure via annular inlet 162 and through a pluralityof apertures 1615 in hub 161. In one embodiment, the apertures 1615distribute the fluid in a radial direction (shown by arrows extendingfrom hub 161) towards the inner surface 171 of shell 170. As the wheel150 rotates in direction 155 (see FIG. 7C), centrifugal forces pushfluid to the inner surface 171 of the shell, and, as noted above, fluidin gap 1655 may cool shell 170. As the wheel rotates about central axis190, the groove 370 imparts a force to the fluid in the gap 1655 in anaxial direction away from a first end 172 of the wheel 150 and toward asecond end 174 of the wheel 150. In this manner, the groove 370 helps tocirculate fluid within the wheel 150 and to mix high temperature fluidwith lower temperature fluid injected from apertures 1615. The groove370 also increases the surface area of the inner surface 171 exposed tocoolant, enhancing heat exchange between the shell 170 and coolant.Fluid is removed via siphon 180, which is in fluid communication withoutlet 167.

As shown in FIG. 7G, a shoe 184 may be coupled to the distal end 182 ofa stationary siphon 180. The shoe 184 may have a mouth 185 flanked by askirt portions 1845. The cage 160 has a plurality of apertures 1605 thatallow fluid to pass from the gap 1655 to the mouth 185. The mouth 185may be in fluid communication with the siphon 180, which, in turn, is influid communication with the outlet 167 (see FIG. 7E). Viewing FIG. 7F,the wheel may be filled with fluid (not shown) up to the level of themouth 185 of the shoe 184. The shoe 184 is preferably made with Teflonor other low friction and/or sacrificial material to prevent or minimizecatastrophic failure if the stationary shoe 184 contacts any other partof the fast rotating spinner wheel 150.

In some embodiments, the shoe 184 is positioned with a small clearance(between about 3-6 mm or any subrange between) between the mouth 185 andthe inner diameter of the cage 160. Therefore, most of the volume ofcoolant within the wheel 150 resides in gap 1655 between the cage 160and the inner surface 171 of the shell 170 (see FIG. 7C). This iscontrary to most conventional designs, which fully flood a spinner wheelwith coolant.

Returning to FIG. 7E, in some embodiments, the lateral position of thesiphon 180 between first end 172 and second end 174 may correspond tothe approximate location that molten material initially contacts theouter surface 1705 of shell 170. This configuration allows hightemperature fluid near the inner surface 171 of the shell 170 to travelthe shortest path to the siphon mouth 185 (see FIG. 7F). In alternativeconfigurations, the siphon 180 may have a lateral position that isoffset from the point of contact for molten material, and one or moregrooves 370 may impart a force to move fluid toward the mouth 185.

In these and other embodiments, one or more helical grooves 370 may beconfigured to impart a force to move fluid from either or both first andsecond ends 172, 174 toward the siphon 180 and more preferably to itsmouth 185 (see FIG. 7F). For example, a first helical groove 370 in theinner surface 171 of the shell 170, positioned at least between thefirst end 172 of the wheel and the siphon 180, may have a helical shapethat is in a clockwise or counter-clock wise direction (depending on thedirection of rotation of the wheel 150) to impart a force to move fluidtoward the siphon 180. In addition or alternatively, a second helicalgroove 370 positioned at least between the second end 174 of the wheeland the siphon 180 may have a spiral path in the opposite direction asthe first groove 370. Together, the first and second grooves 370 maycooperate to impart a force to move fluid toward a means to evacuate itfrom the cylinder, such as a siphon.

In addition or alternatively, all or a portion of one or more grooves370 may have a pitch with respect to a central axis 190 such that it hasa uniform pitch or a varying pitch. Alternatively, a shell 170 mayneither comprise a blade nor groove 370 on or in its inner surface 171.

Turning to FIG. 8B, one alternative to a shoe 184 (see FIG. 7F) is ascoop 186. The scoop 186 may be coupled to the siphon 180 such that themouth 185 of the scoop 186 is in fluid communication with the siphon180. In comparison with a shoe 184, a scoop 186 has a narrowercross-sectional area, resulting in less drag from the fluid it contactsand therefore less torque on the siphon 180. In preferred embodiments,both the shoe 184 (see FIG. 7G) and the scoop 186 (see FIG. 8C) have acurved portion that redirects incoming fluid up into the siphon 180.

Turning to FIG. 9A, an alternative embodiment of the wheel 150 is shown.The wheel 150 comprises a shaft 164, a blade 375, a cage 160, a hollowcylindrical shell 170, an endcap 175. The blade 375 and the cage 160 maybe positioned within the shell 170. A plurality of fasteners 169 maycouple the endcap 175 to the cage 160. The endcap 175 may have aplurality of flanges 1752, and the endcap 175 may be coupled to theshell 170 through a plurality of notches 1752 sized to operably couplewith the flanges 1752. The blade 375 may be positioned around the shaft164. In some embodiments, the blade 375 may be coupled to the shaft 164and/or the cage 160 such that it rotates with the wheel 150.

Viewing FIG. 9C, the wheel 150 may further comprise an inner endcap 1751coupled to a rotatable journal 154. The journal 154 may be powered by adrive shaft 153 (see FIG. 6), and the journal may translate shaft drivepower to rotate the wheel 150 in a direction 155 (see FIG. 9A) about acentral axis 190.

A cavity 165 within the wheel 150 may be defined by an outer endcap 175,an inner endcap 1751, and an inner surface 171 of the shell 170. Forembodiments comprising a cage 160, the cavity 165 may be formed in partyby a gap 1655 between the outer diameter of the cage 160 and the innersurface 171 of the shell 170. The cavity 165 and/or gap 1655 may bepartially or substantially fully filled with fluid.

Viewing FIG. 9A, the wheel 150 may further comprise an inlet plate 1665and outlet plate 166 disposed around shaft 164. In some embodiments, theplates 166, 1665 may be conically shaped. Alternative embodiments maynot comprise an inlet plate 1665 and/or outlet plate 166.

Fluid may circulate through wheel 150 in either a partially orsubstantially fully filled configuration. Returning to FIG. 9C, fluidenters the wheel via inlet 162. An annular shaft 164 may comprise aplurality of apertures 1645 in fluid communication with the inlet 162and cavity 165. As fluid enters the cavity 165 from apertures 1645, aplate 1665 may help direct the fluid in a radial direction away from thecentral axis 190 and toward the inner surface 171 of the shell 170.Fluid may travel through the gap 1655 and through and around the blade375 from a first end 172 of the wheel 150 to a second end 174 of thewheel 150. The blade 375 and/or groove 370 may impart a force on thefluid to move it toward an annular outlet 167. A plate 166 may helpconcentrate the flow of fluid from the cavity 165 to the outlet.

The embodiment of the helical blade 375 shown in FIG. 9A has four loopswith a uniform pitch. Alternative embodiments may have one or moreblades with more or fewer loops. Blades 375 in such alternativeembodiments may have a uniform or variable pitch. Likewise the groove370 may have a uniform or variable pitch. Alternative embodiments mayneither comprise a blade 375 and/or a groove 370.

Turing to FIGS. 10A and 11A, an alternative embodiment of a spinnerwheel 150 is shown. A wheel may comprise a hub 168 and a blade 375positioned within a shell 170. The shell 170 may comprise an outersurface 1705 and an end 175. In some embodiments, the end 175 of theshell 170 may form a unitary part of the shell 170. In alternativeembodiments, the end 175 may be a separate component (see FIG. 12).Bores 1757 in the end 175 may align with bores 1685 in the hub 168 (seealso FIG. 10B), and the end 175 may be coupled to the hub 168 byfasteners (not shown). In addition, the end 175 of the shell 170 mayhave a counter-bore 1755 (see FIG. 10C) sized to couple with the end1686 (see FIG. 10C) of hub 168. A helical blade 375 may be positionedaround the hub 168. In addition or alternatively, the wheel 150 maycomprise a cage 160 (see FIGS. 7-9).

Turning to FIG. 10C, a cavity 165 may be defined by the end 175, theinner surface 171 of the shell 170, and an outer surface of the hub 168.The hub 168 may have a plurality of inlet apertures 1682 and outletapertures 1687 in fluid communication with the cavity 165.

In preferred embodiments, the outer diameter of the blade 375 is incontact with the inner surface 171 of the shell 170, and the blade 375comprises a material suitable (such as stainless steel) for conductingheat from the shell 170. In this manner, the blade 375 may act as a heatsink for the shell 170. The surface area of the blade 375 that isexposed to the coolant is preferably significantly greater than thesurface area of the inner surface 171 of the shell 170.

In some embodiments, the blade 375 may be fixedly attached to the innersurface 171 of the shell 170 by welding or other coupling means. Inaddition or alternatively, the inner diameter of the blade 375 may beapproximately sized to the outer diameter of the hub 168 such that fluidflowing from the inlet aperture 1682 must travel through the helicalblade 375 to reach the outlet aperture 1687. In alternative embodiments,a gap (not shown), allowing fluid to flow around the blade 375, may bebetween either the inner diameter of the blade 375 and the outerdiameter of the hub 168 and/or the outer diameter of the blade 375 andthe inner surface 171 of the shell 170. For example, in one embodiment,the blade 375 may be coupled to the inner surface 171 of the shell 170(or a cage 160) and there may be a gap (not shown) allowing fluid toflow between the inner diameter of the blade 375 and the outer diameterof hub 168. In an alternative embodiment, the blade 375 may be coupledto outer diameter of the hub 168 and there may be a gap (not shown)allow fluid to flow between the outer diameter of the blade 375 and theinner surface 171 of the shell 170.

Viewing FIG. 10C, in operation, the wheel 150 may rotate in a direction155 (see FIG. 10A) about a central axis 190, and molten material (notshown) may be applied to the outer surface 1705 of the shell 170.Through conduction, heat from the outer surface 1705 of the shell 170may move to the inner surface 171 of the shell and, in some embodiments,one or more blades 375 in contact with the inner surface 171. To coolthe shell 170, coolant (not shown) may enter the wheel 150 through acentral inlet 162. The inlet 162 may be in fluid communication withapertures 1682 in the hub 168. From the inlet 162 and through theaperture 1682, coolant may enter the cavity 165 and travel toward theinner surface 171 of the shell 170. In some embodiments, the coolantmust travel through a helical blade 375 to reach outlet apertures 1687in the hub 168. The outlet apertures 1687 may be in fluid communicationwith an annular outlet 167, and coolant may travel from the cavity 165through the apertures 1687 to the outlet 167 to exit the wheel 150.

FIG. 10C shows a helical blade 375 with four loops and a gap 1655between an end of the blade 375 and the outlet aperture 1687. The blade375 imparts a force on the fluid in the cavity 165 to move the fluidtoward the outlet aperture 1687 and across the gap 1655. Turning to FIG.11C, a helical blade 375 is shown with eight loops. Viewing FIG. 11C,the end of the blade 375 may be positioned proximate to the outletaperture 1687 to convey fluid directly into the outlet aperture 1687.Alternative embodiments of one or more blade 375 may have 1-20 loops.Plural blades 375 may be positioned in parallel (i.e., at leastpartially overlapping—see, e.g., FIG. 2A) and/or serially (e.g.,end-to-end).

In some embodiments, the cavity 165 may be partially filled with coolantsuch that less than 80% or 70% or 60% or 50% or 40% or 30% or 20% or 10%or 5% or 1% of its volume is filled with coolant. In alternativeembodiments, the cavity 165 may be substantially fully filled withcoolant such that more than 80% or 85% or 90% or 95% or 99% and up to100% of its volume is filled with coolant. (To maintain fluidcommunication with the fluid, an outlet aperture 1687 may be designedwithin a hub 168 to be more or less proximate to the inner surface 171of the shell 170 than is shown in FIGS. 10-11.)

The blades shown in FIGS. 10A and 11A have a uniform pitch. In additionor alternatively, all or a portion of one or more blades 375 may have apitch with respect to a central axis 190 (see FIGS. 10C and 11C) suchthat it has a uniform pitch or a varying pitch. In addition oralternatively, a shell 170 may comprise a groove 370 on or in its innersurface 171 (see e.g., FIG. 9A).

As shown in FIGS. 7-11, inlet apertures 1615, 1645, 1682, which are influid communication with an inlet 162, may take many forms. In someembodiments, an inlet aperture 1645, 1682 may be proximate to a firstend 172 of the wheel 150 (see FIGS. 9-11). In addition or alternatively,an inlet aperture 1615 may be proximate to a second end 174 of the wheel150 (see FIGS. 7-8).

Turning to FIG. 12, a wheel 150 may comprise a hollow shell 170 and anendcap 175. An interior of the shell 170, enclosed by cover 175, may befilled with a liquid with a relatively high specific heat, such as wateror ethylene glycol. The shell 170 may comprise a first end 172, a secondend 174, and a groove 370. The groove 370 may be positioned in or on theinner surface 171 of the shell 170 and move the liquid proximate to theinner surface 171 of the wheel from the first end 172 toward the secondend 174. The groove 370 may comprise a fixed, i.e., uniform, or variablepitch spiral shape. FIG. 12 shows a variable pitch helical shape with atleast four spiral loops. The groove 370 helps the fluid to circulatewithin the shell 170, which facilitates cooling and prevents damage tothe shell 170. In addition or alternatively, a blade (not shown) may bepositioned within the shell 170, including on the inner surface 171.

At least a portion of the circumferential outer surface of wheel 170 maycomprise any material suitably resistant to heat damage, such as metalor ceramic. The wheel 170 may further comprise material permitting heattransfer from its outer surface 1705 to its inner surface 171.

In the context of spinner wheels 150, the apparatus and methodsdescribed herein provide several significant advantages over anunmodified wheel.

First, for a spinner wheel 150 comprising a groove 370 and/or blade 375and a cavity 165 that is partially or substantially fully filled withfluid, the groove 370 and/or blade 375 may promote significantlyenhanced fluid circulation within the wheel 150.

Second, in addition or alternatively, fluid circulation may be enhancedby forcing fluid to travel from a first end 172 of the wheel 150 to asecond end 174 of the wheel 150. For example, as shown in FIGS. 9C, 10C,and 11C, an inlet aperture 1645, 1682 may be positioned proximate to afirst end 172 of the wheel 150 and either an outlet 167 and/or outletaperture 1687 may be positioned proximate to a second end 174 of thewheel 150. In addition or alternatively, as shown in FIG. 7E, an inletaperture 1615 in a hub 161 may inject fluid into the cavity 165 underpressure and direct it to the first end 172 (see arrows pointing fromhub 161).

Third, a wheel 150 comprising a siphon 180 may also promote fluidcirculation and/or significantly reduce the volume of fluid needed tocirculate within the cavity 165.

The first, second, and/or third advantages may apply even if the spinnerwheel 150 is not exposed to high temperatures.

Fourth, for a spinner wheel 150 used to spin metal or other moltenmaterials applied to the outer surface 1705 of a shell 170, a groove 370and/or blade 375 may facilitate heat transfer from the shell 170 to acoolant. For example, the groove 370 may increase the surface area ofthe inner surface 171 to which the coolant is exposed. In addition oralternatively, the blade 375 may conduct heat from the shell 170, actingas a heat sink.

However, not all embodiments are required to have any or all theforegoing advantages.

EXAMPLES

Numerous industrial applications for the invention are possible. Anydesigner of a pipe or cylindrical system in which fluid must be moved inan axial direction may benefit from the teachings of this disclosure.Specifically, whether a process requires a rotating cylinder to beheated or cooled, the invention is directly applicable. Typical examplesare dryer drums, “Yankee” tissue dryer cylinders, metal spinning drums,mineral wool spinning wheels, textile slashers, corrugator cans,calendar rolls, water tube boiler tubes, and condenser tubs, amongothers. Some specific examples of the invention are as follows.

Prophetic Example 1

Viewing FIG. 1B, a cylinder 100 in a paper making machine may have adiameter of about 1-5 meters (or any subrange between) or preferablyabout 1.52 meters and a length of about 5-11 meters (or any subrangebetween) or preferably about 9 meters. In operation, supply steampressure may be about 600-1000 kpa (or any subrange between) orpreferably 860 kpa with a flow rate of about 7-12 liters per minute (orany subrange between) or preferably about 9.1 liters per minute. Atsteady state conditions, the cylinder may be rotated at about 90-200 RPM(or any subrange between) or preferably about 127 RPM.

The blade pitch may be optimized according to the operating rotationalvelocity of the cylinder. Based on the foregoing preferred operatingconditions, the first loop proximate to the first end 102 forms a pitchwith the central axis 190 that is substantially perpendicular. Thesecond pitch 1310 (approximately 83 degrees) and successive pitches 1312(approximately 72 degrees), 1314 (approximately 58 degrees), 1316(approximately 35 degrees), 1318 (approximately 14 degrees) haveprogressively smaller slopes until the end of the blade 300 issubstantially perpendicular with the central axis 190. Accordingly, thedistance 1320 (approximately 15 cm) between the first spiral and thesecond spiral may be less than the distance 1322 (approximately 25 cm)between the second and third spirals, which is less than the distance1324 (approximately 64 cm) between the third and fourth spirals.Likewise, the distance 1326 (approximately 209 cm) between the fourthand fifth spirals may be greater than the distance 1324 but less thanthe distance 1328 (approximately 323 cm) between the fifth and sixthspirals.

The velocity of the condensate within the cylinder 100 accelerates alongthe longitudinal axis of the cylinder 100. For condensate contacting thefirst loop proximate to the first end 102 of the cylinder 100, thevelocity is almost zero while condensate proximate to the second end 104is approximately 1.1 m/s. In some siphon configurations, this may allowthe condensate to be evacuated through a rotating siphon with little orno blow through steam.

Prophetic Example 2

Cylinder 100 in a paper making machine may have a diameter of about 1.52meters and a length of about 9 meters. In operation, supply steampressure may be 860 kpa with a flow rate of 9.1 liters per minute. Atsteady state conditions, the cylinder may be rotated at 96 RPM. Thevelocity of the condensate within the cylinder 100 accelerates along thelongitudinal axis of the cylinder 100. For condensate contacting thefirst loop proximate to the first end 102 of the cylinder 100, thevelocity is almost zero. In this example, condensate proximate to thesecond end 104 is approximately 0.78 m/s. In some siphon configurations,this may allow the condensate to be evacuated through a rotating siphonwith less than about 10% blow through steam.

Prophetic Example 3

Viewing FIG. 12, a wheel 150 comprising a shell 170 may rotate at about4,000-7,000 RPM (or any subrange between) or preferably about 5,000 RPM.A length 176 of the shell may be about 20-50 cm (or any subrangebetween) or preferably about 32 cm and the diameter 177 may be about30-70 cm (or any subrange between) or preferably about 56 cm. Water maycirculate within the wheel at about 20-60 liters per minute (or anysubrange between) or preferably about 40 liters per minute.

Prophetic Example 4

Viewing FIG. 7E, a wheel 150 comprising a shell 170 may rotate at about4,000-7,000 RPM (or any subrange between) or preferably about 5,000 RPM.A length 176 of the shell may be about 20-50 cm (or any subrangebetween) or preferably about 32 cm and the diameter 177 may be about30-70 cm (or any subrange between) or preferably about 56 cm. Ethyleneglycol may circulate as a coolant within the wheel at about 10-60 litersper minute (or any subrange between) or preferably about 48 liters perminute. Coolant flow into the wheel 150 may be regulated to maintaincoolant levels approximately at the level of the mouth 185 of the siphon180 (see FIG. 7F). The coolant may be introduced via inlet 162 under apressure of about 300-600 kpa (or any subrange between) or preferablyabout 425 kpa.

In conclusion, the embodiments and examples shown in the drawings anddescribed above are exemplary of numerous others that may be made withinthe scope of the appended claims. It is contemplated that numerous otherconfigurations may be used, and the material of each component may beselected from numerous materials other than those specificallydisclosed.

In conclusion, in the interest of clarity, not all features of an actualimplementation—e.g., dimensions, tolerances, etc.—are described in thisdisclosure. As used in this disclosure, the terms “about,”“approximately,” and “substantially” apply to all numeric values,whether or not explicitly indicated. These terms generally refer to arange of numbers that one of skill in the art would consider equivalentto the recited values (i.e., having the same function or result). Inother words, such words of approximation refer to a condition ormeasurement that would be understood to not necessarily be absolute orperfect but considered close enough by those of ordinary skill in theart to warrant designating the condition as being present or themeasurement being satisfied. For example, a numerical value ormeasurement modified by a word of approximation may vary from the statedvalue by 1, 2, 3, 4, 5, 6, 7, 10, 12, and up to 15%.

It will be appreciated that, in the development of a product or methodembodying the invention, the developer must make numerousimplementation-specific decisions to achieve the developer's specificgoals, such as compliance with manufacturing and business-relatedconstraints, that will vary from one implementation to another.Moreover, it will be appreciated that such a development effort may becomplex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

No special definition of a term or phrase, i.e., a definition that isdifferent from the ordinary and customary meaning as understood by thoseskilled in the art, is intended to be implied by consistent usage of theterm or phrase herein. The words and phrases used herein should beunderstood and interpreted to have a meaning consistent with theunderstanding of those words and phrases by those skilled in therelevant art. For example, an embodiment comprising a singular elementdoes not disclaim plural embodiments; i.e., the indefinite articles “a”and “an” carry either a singular or plural meaning and a later referenceto the same element reflects the same potential plurality. A structuralelement that is embodied by a single component or unitary structure maybe composed of multiple components. Ordinal designations (first, second,third, etc.) merely serve as a shorthand reference for differentcomponents and do not denote any sequential, spatial, or positionalrelationship between them.

The foregoing description of the embodiments of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the preciseform(s) disclosed, and modifications, and variations are possible inlight of the above teachings or may be acquired from practice of theinvention. The embodiments were chosen and described in order to explainthe principles of the invention and its practical application to enableone skilled in the art to utilize the invention in various embodimentsand with various modifications as are suited to the particular usecontemplated. It is intended that the scope of the invention be definedonly by the following claims, as amended, and their equivalents.

DESCRIPTION OF REFERENCED NUMERALS 100 cylinder 101 inner surface 102first end of cylinder 100 104 second end of cylinder 100 110 supportmember 120 shaft 124 condensate outlet 150 spinner wheel 151 motor 152belt 153 shaft 154 journal 1545  bore 155 direction of rotation 158coolant exchanger 160 cage 1605  apertures in cage 160 1608  bore 161hub 1615  aperture for inlet 162 162 inlet 164 shaft 1645  aperture forinlet 162 165 cavity 1655  gap 166 outlet plate 1665  inlet plate 167outlet 168 hub 1682  aperture for inlet 162 1685  bore 1686  end of hub168 1687  aperture for outlet 167 169 fastener 170 shell 1705  outersurface of shell 170 171 inner surface of shell 170 172 first end 174second end 175 outer wheel endcap 1751  inner wheel endcap 1752  flange1753  notch 1755  counter bore 1756  bore 1757  bore 176 wheel length177 wheel diameter 180 siphon 181 bushing 182 distal end of siphon 180184 shoe 1845  skirt 185 mouth 186 scoop 190 central axis 200 rotarysiphon 300 variable pitch blade 301 second variable pitch blade 305uniform pitch blade 310 first blade segment 311 second blade segment 312third blade segment 320 blade width 322 blade height 324 blade pitch 370groove for moving liquid 375 helical blade 500 fluid or condensate1310-1318 pitch with respect to longitudinal axis 190 1320-1328distances between loops of blade 300 2320-2336 distances between loopsof blades 300 and 301 3310-3316 ~45 degree pitch for blade 300 3320-3326distances between loops of blade 300

1. A method for installing an apparatus for moving condensate in anenclosed, rotating cylinder for drying cellulosic pulp comprising: a.positioning at least one blade along at least a portion of an innersurface of the cylinder such that the blade rotates with the cylinder;b. the blade having a first end, a second end, and a central axis; c. atleast one end of the blade is positioned proximate to a siphon; d.wherein at least a first portion of the blade proximate to the first endis substantially perpendicular to the central axis; e. wherein at leasta second portion of the blade proximate to the second end issubstantially parallel to the central axis; f. wherein the blade has apitch relative to the central axis varying from about 90 degrees at thefirst portion to about 0 degrees at the second portion; and g. the pitchdecreases from the first portion to the second portion.
 2. The method ofclaim 1, further comprising: a. wherein the blade is a first blade; andb. positioning a second blade along at least a portion of an innersurface of the cylinder such that the second blade rotates with thecylinder.
 3. The method of claim 2, wherein the second blade has a firstend positioned proximate to the second end of the first blade.
 4. Anapparatus for moving fluid in a rotating cylinder comprising: a. a bladeshaped in a spiral path having a central axis and a diameter of betweenabout 1 m and about 3 m; b. wherein at least a portion of the spiralpath has a pitch relative to the central axis greater than about 5degrees; c. a rotatable cylinder; d. wherein the blade is positionedalong at least a portion of an inner surface of the cylinder such thatthe blade rotates with the cylinder; and e. wherein the cylinder isheated with steam.
 5. (canceled)
 6. The apparatus of claim 4, whereinthe blade is fixedly attached to the inner surface.
 7. The apparatus ofclaim 4, wherein the blade is removably attached to the inner surface.8. (canceled)
 9. The apparatus of claim 4, wherein a first end of theblade has a pitch that is different from a pitch at a second end of theblade.
 10. The apparatus of claim 4, wherein the pitch is substantiallyuniform across the blade from a first end to a second end.
 11. Theapparatus of claim 4, wherein at least a portion of the blade has aheight of less than about 10 cm.
 12. The apparatus of claim 4, furthercomprising fluid and a flow path along at least a portion of the blade,wherein the flow path comprises turbulent flow.
 13. An apparatus formoving fluid in a rotating cylinder comprising: a first blade shaped ina spiral path having a central axis and a diameter of between about 1 mand about 3 m; wherein at least a portion of the spiral path has a pitchrelative to the central axis greater than about 5 degrees; a secondblade having an end positioned proximate to an end of the first blade;and wherein the pitch of at least a portion of the first blade isdifferent than a pitch of at least a portion of the second blade. 14.The apparatus of claim 4, wherein the spiral path comprises at least one360 degree loop.
 15. The apparatus of claim 4, wherein at least aportion of the blade has a pitch relative to the central axis of atleast about 25 degrees.
 16. The apparatus of claim 4, wherein at least aportion of the spiral path has a pitch relative to the central axis ofabout 45 degrees.
 17. The apparatus of claim 4, wherein at least aportion of the blade has a pitch relative to the central axis of atleast about 60 degrees.
 18. The apparatus of claim 4, wherein a firstend of the blade has a pitch relative to the central axis of at leastabout 45 degrees, and wherein a second end of the blade has a pitchrelative to the central axis of less than or equal to about 45 degrees.19. The apparatus of claim 18, wherein the blade has a pitch relative tothe central axis varying from about 90 degrees at the first end to about0 degrees at the second end.
 20. (canceled)
 21. (canceled)
 22. A systemfor making paper comprising: a. a rotating hollow cylinder having aninlet and outlet and an inner surface and outer surface; b. a continuouspaper web in contact with the outer surface of the cylinder; c. steamintroduced through the inlet to condense on the inner surface of thecylinder; d. at least one blade positioned on an inner surface of thecylinder, wherein the blade extends in a spiral path across at least aportion of a length of the cylinder; e. the blade configured to directcondensate to a flow path carrying the condensate to the outlet of thecylinder. 23.-92. (canceled)
 93. The system of claim 22, wherein atleast a portion of the blade has a pitch relative to a central axis ofat least about 25 degrees.
 94. The system of claim 22, wherein a firstend of the blade has a pitch relative to the central axis of at leastabout 45 degrees, and wherein a second end of the blade has a pitchrelative to the central axis of less than or equal to about 45 degrees.